Niemcza diorites and moznodiorites (Sudetes, SW Poland): a record of changing geotectonic setting at ca. 340 Ma

摘要: Granites sensu lato in the Sudetes intruded several episodes during Variscan orogeny recording different stages of crust and mantle evolution. Correlating precise ages with geochemistry granites provides information on evolution these sources within orogen. The intrusive rocks from Niemcza Zone (Bohemian Massif, Sudetes, SW Poland) include undeformed dioritic to syenitic magmatically foliated granodiorites. In this study we analysed low SiO2 (48–53 wt.%) monzodioritic Przedborowa Koźmice. monzodiorites contain late-magmatic zircons 341.8 ± 1.9 Ma for 335.6 2.3 Koźmice, interpreted as emplacement magmas. Older are lower K, Mg, Rb Ni than Koźmice similar compositional trend is also observed Central Bohemian Plutonic Complex. implication that underlying became more enriched ca. 342 336 Ma, probably following collision Saxothuringian Moldanubian/Lugian domains. magmatism related occurred 12 later Complex, but was accompanied by a change magma chemistry high-K (Przedborowa) shoshonitic (Koźmice, Kośmin enclaves) ultrapotassic (Wilkow Wielki)